This invention relates to the field of audio frequency recording apparatus, and particularly to time indexed voice recordings made on magnetic tape media.
In order to study aircraft pilot and crewmember responses during actual airborne missions and simulated missions in ground based equipment it is often necessary to record the sequence of mission event related vocal comments made by the aircraft crewmembers. This vocal recording is necessary since the occurrence of mission related events often cannot be determined solely from the otherwise recorded aircraft, function parameters crewmember performance events, or physiological data changes. Such vocal recording is often accomplished, by providing a full time voice tape recorder connected with the aircraft communication system. The resulting recording therefore provides a permanent record of mission related comments.
Heretofore crewmembers using a recorder of this type have often been asked to report mission times along with their voiced descriptions of mission events. Using this arrangement, however, at playback, following the mission, a stop clock is often needed to determine when intervening mission events occurred. Such playback is a very time consuming task, however, especially since pilots often forget to..re port the time on their voice recordings. In such instances it is necessary to rewind the tape to the last time report, start a stop clock, and advance the tape in real time to the verbal report in interest in order to obtain its precise timing. This process often must be accomplished for many events of interest on each recorded tape.
In addition to being time consuming, this method is prone to errors especially from accidental tape stoppage or from tape stretching or other unpredicted events. In addition, the time required to transcribe such tapes restricts the utility of the obtained data since a timely turn around is often required for optimal data usage.
By using the time coded voice recording arrangement of the present invention, however, a recorded tape can be positioned anywhere along its length during playback and the recorded time immediately shown on the display provided. This capability which is in fact a manual random search mode, provides that once a specific voice signal is located, its time of occurrence is immediately known or can be precisely calculated. With this capability, timing from the last voice recorded time marker on a tape is no longer necessary.
The prior patent art includes several examples of recording systems which are of interest with respect to the recorder of the present invention; included in these patents is the patent of E. A. Boniface, U.S. Pat. No. 3,327,067 which is concerned with an aircraft cockpit sound recorder of the type used for aircraft accident investigation. The Boniface patent discloses the use of emergency energization of the recorder together with an impact operated switch in order to terminate the recorder operation at the time of an aircraft crash. The Boniface recorder also uses a continuous recorder or circulating loop recording media and employs an erase operation upon normal landing of the recorder monitored aircraft. Although it is also intended for use in an aircraft the recorder system of the present invention is distinguished over the Boniface recorder by the absence of time signals, by the Boniface back of recorder portability and other aspects described below.
Also included in this patent art is the patent of L. H. Poutney et al U.S. Pat. No. 3,657,488, which relates to a work study recording system intended for use in the analysis of operator performance in a manufacturing environment. The Poutney et al patent includes the use of a recorded timing signal to identify the start and finish of each operation performed by the timed operator and uses the same one data channel of the recorded media for both the time signal and recorded voice data. The time coding arrangement, the single signal recording channel, and other aspects of the Poutney apparatus are distinguished from the arrangement of the present invention.
This patent art also includes the patent of R. L. Murphy et al, U.S. Pat. No. 4,012,784, which is concerned with a two track cassette tape voice recording apparatus in which recordings are made on multiple different tapes, one for fast recall purposes. The Murphy patent also uses a combination of time signals and message start indication signals on the second of the recording tracks. The Murphy et al recorder is especially adapted for use in monitoring police, fire, and aircraft communication and contemplates intermittent actuation of the employed recording tapes with the message beginning indications in the time track being recorded at a special low frequency in order that they be inaudible during normal playback but become audio active during high speed transportation of the tape--for tape positioning purposes It is also notable that the Murphy et al recording arrangement contemplates use of binary coded decimal signals in a frequency shift keying arrangement for recording in the time track of the magnetic tape. Therefore at least the tape movement practices, the time signal coding, and the entertaining type of recording apparatus used in the present invention distinguish the present invention from the Murphy et al patent.
Also included in this patent art are the patent of C. Harada et al, U.S. Pat. No. 4,729,381, which is concerned with a medical recording apparatus for such information as blood pressure, heart rate, and breathing rate and is especially the usable in the generation of record sheets. The Harada et al apparatus includes provision for recording the times of detection of the medical information and means for controlling the recording device so as to record the medical indicia at the predetermined recording positions of the chart area. In the Harada et al patent the term "recording" appears to especially relate to the generation of a mark along a time graduated scale.
The recording accomplished according to the present invention is therefore believed to be distinguished over both these individual references and combinations of these references since inter alia the form of recording used in the present invention is distinguishable from that used in the prior art references and periphial aspects of the present invention recorder are also readily distinguished from those of the prior art.